Cyanamid-oven.



G. E. COX.

CYANAMID OVEN.

APPLICATION FILED JULY 24. ms.

Patented Dec. 30, 1919.

UNITED STATES PATENT OFFICE.

GEORGE E. COX, N IAGABAIAIJLS, NEW YORK, ASEIGNOR T0 AMERICAN CYANAMIDCOMPANY, OF NEW YORK, N. Y., A CORPORATION OF MAINE.

GYANAMID-OVEN.

To all whom it may concern:

Be it known that I, Gnonun E. Cox, a citizen of the United Statesresiding at Niagara. Falls, in the county of- Nia are and State of NewYork, have invents certain new and'useful Improvements in Cyanamid-Ovens;and I do hereby declare the followingrto be a. full, clear, andexact descri tion of the invention, such as will enab e others skilledin the art to which it appertains to make and use the same. Thisinvention relates to cyanalnid ovens and has for its object to improvethe linings of the'same in a manner less costly than has been heretoforeproposed.

With this object in view the invention consists in the novel parts andcombinations of parts all as will .bemore fully hereinafter describedand particularly pointed out in the claims.

Referring to the accompanying drawings forming a art of thisspecification in which like numerals designate like parts in all the,views:

Figu oven lined according to this invention;

Fig. 2 is. a detail view taken on the line 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1 showing 8. =Sr(1JmeWh8.t modifiedform of the invention; an a 'Fig. 4 is a detail view taken on the line Hof Fig. 3.

In order that the recise invention may be the more clearly un erstood,it is said:

[In the manufacture ofcyanamid it has been heretofore the practice totake a finely ground carbid and insert the same into a container. Thiscontainer filled with its charge of carbid is placed in. an oven linedwith suitable refractory and insulated material- A suitable electricresistor is inserted axially through the container in a space providedtherefor.

The lid is placed on the oven, nitrogen admitted and the current turnedon to the resistor. At a temperature upward of 800-1000 G. the hotcarbid adjacent to the resistortakes' up nitrogen and is convented intocyanamid. This reaction progreases outwardly throughout the massuntilthe whole more or less completely converted to 'eyanamid, when the saidmass is p. p p cool. The container with its content t .Wof c H left"thenremoved anll the oven re 1 is a sectional view of a cyanamidspecification of Letters Patent. Patented Dec. 30, 1919.

llpplication filed July 21, 1919. Serial No. 312,183.

and expense, and it becomes dented and bat- B0 tered through handlingwhich makes it ditliculs to distribute its content of solid cyanam1 Inorder to obviate this difficulty and especially because of the excessivecost of metal containers, a substitute for the same was found,consisting .in a paper sleeve which was inserted into the oven and thenfilled with carbid, after which nitrificationwas started in the usualmanner. This paper sleeve must be manufactured from stout paper and ofdefinite dimensions and even with the greatest care it, wouldfrecpliently tear or spit from the pressure of t e contained powderedcarbid. An annular space had to be left between the paper container andthe oven for inserting the proper equipment for placing the paper andholding it in place during the fillin with carbid as well asto assist inthe distribution of the nitrogen. This annular space re- A containers itwas found that the ordinary cyanamid oven, cylindrical in form andprovided with the usual refractory lining, could be lined with a singlesheet of paper or preferably corrugated strawboard; the usual papercylinder; 'forformin a space for the resistor could be inserte and thenthe whole oven could be filled with carbid. all as will be clear fromthe prior U. S. Patent #1315678, dated Sept. 9, 1919, to W. II.Middleton, assigned to the American Cyanamid Company, and entitledProcess of manufacturin cyanamid. In this manner the strawboar or papercould he merely laid around the inside wall of the oven with'a suitablelap without special formi Operating according to this latter proc fiurea given oven would hold say 35 per cent. more carbid than where the saidprior paper sleeve was used and nearly 50 per cent. more than where thea metal container was used, and this without any change whatever in thestructure of the that a heavy cox-rug oven itself. In such cases thenitrogen was led through a. hole at the side and bottom of the ovenwhich was covered with broken stri s of corrufited strawboards extendingtot e center to and also tothe top of the com ated lining and in thisway nitrogen was istributed through the broken up strawboard both to thecenter and to the to of the oven.

This latter method gave very excellent results, because it produced ahigh fixation and a large capacity per oven, but it is necesspgg atedstrawboardbe u for in case of using-a light lain per where the ovenwalls are smoot i it w1'l not allow for a free passage of nitrogen arounthe carbid, and'in the case .of an' uneven projection from the ovenwalls, with this lighter paper there is e. perienced a com siderableloss in the tearing of the paper. Also, one cannot rely on an absolutelyeven distribution of nitrogen 'in and around the mass in this saidprocedure, for while the fixation is high it is not as uniform as mightbe desired in all cases.

In this invention, on the other hand, I have found it desirable to linethe inside wall of the oven with a piece of wire screening, or netting,and place the plain paper against this said wire screenin or netting.I'also insert the usual paper cy inder in the center for forming a siace for the resistor and I fill up the whoie oven with oarbid. In placeof using a wire screen, the bricks of the oven lining itself may bemolded or out with projections, the span from ti to tip of which are notso great as the pa 1' lining to tear. Plain paper is then p aoed insideof the oven against the brick work with a suitable la and the operationscarried on as describe above.

In this manner I am able to secure a very uniform flow of nitrogen gasaround and about the carbid which gives-in practice an exceedinglyuniform fixation of the carbid for the formation of cyanamid. It alsogives as high a fixation as is obtained by the previous methods. Thismethod also has the advantage 'of allowing me to usea cheaper form oflining than is' possible by the previous process and with less troubleand diiliculty in handlin the same. I re fer to have the oven s ightlytapere as shown, it being somewhat largcr in diameter at the top than atthe bottom, because when the carbid fixes the nitrogen with theformation of cyanan'lid, the latter shrinks away from the oven liningsomewhat, and by the use of a tapered oven the charge may be more easilywithdrawn. "I v 7 Referring to the accompanying drawings, 1 indicatesany suitable outer shell, 2 any suitable refractory lining, preferablytapered as shown, 3 a cover having a refractory lining 4, and thedepending rim 5, dipping Y near the bottom I provide the nitrogen innitroge to slowinto a sand seal 6, held by the annular member 7 asshown.

On the inside surface of the refractory lining "Z, I preferably la wirecloth, or a and msi e the netting 8 1' wire netting lay-prefera lysmooth paper sheets 9. the center of the oven place the paper or othercombustible tube 10 for the accommoside let 12. Between the inlet 12 andthe tube 11 I ma place a tube of crumpled up, or corrugated paper 13 asshown, in or er to lead dation of the resistor 11, and at the 13, I maylay wire cloth 14 as shown in F1g. 1, or it may be omitted as shown-1nFig. 3, if the tube 13 is made sufiiciently strong to keep open apassage for. the nitrogen.

'rtion' 15 of the paper 9 may also extend above the wire cloth 14 asshown in Fig. 1. The modifiedconstruction illustrated in Figs. 3 and4'is substantially the same as except the inside surface of therefractory lining is roughened as indicated at 18. The prowetions 19 aresuitably molded in the ricks, but may be otherwise roduced, are spacedsufficiently c use to each oth prevent the tearing of the paper lining20. 21 represents books that areplaced in the carbid charge 22 to fa'ilitate the with-P. drau'al of the formed cyanamidfrom the theresistor, and above this tube oven.

It will thus be seen that I have discovered that the space left'by themeshes of wire cloth, or a wire screen, will not be filled up after thecombustible paper stroyed, and that it will be suliieient to furnish apassage for the feeding of the nitro n in the process. In other words,it will now be clear that I have dismvered, it is not necessary to even0 to the expense an trouble that are inc dent to the highl ellicientprocess disclosed in the said Mid leton application above mentioned; forI may even avoid a corrugated lining for theoven, and

employ plain paper, provided there are present supporting pro ectionsfor said paper spaced so close that it will not tear.

Of course, u on nitrification the paper around the insi e of the ovenchars and the ingot of cyanamid shrinks away from the walls andscreening sufficiently, so that if a roper taper is given to the ovenlining 2 it is a simple matter to withdraw the in ot. A crane picks upthe ingot of cyanamid attaching hooks to the rings the iron rods 21, and

oven.

A great advantage in this improved process lies in the fact that a verychea grade of plain paper 9 can be used. T e wire screening 8 may beused over and over again and when the brick in the walls of the ovenlmmg are molded or cut in grooves 18 on the ends of carries itout of thelining 9 is deas by no appreciable replacements am -necessary. Also, aperfectly-uniform passage of nitrogen is thus provided inand around themass 22, and there is combined with the previous advantages claimed forthe full oven, a better reflection ofhe'at to the-mass from the lining2, resulting in more perfect fixation 'at the outside of the ingot 22.As a result the last mentioned previous. process. It is stantially asevident that thoseskilledin the art can vary. this procedure withoutessentially changing its principle-and 'I, therefore, do not wish to be.restricted to the above disclosure, except as may be required bytheclaims.

What I claim is 1. In a cyanam'ui oven rovided with a re fractorylining, the com ination of a combustible, substantially smooth, paperlining and a plurality of supporting means-separated by interstices,located between said refractory linin and said paper lining,subescl'ibed.

2. In a cyanamid oven provided with a refractory lining and a resistorthe combination of a combustible tube surrounding'said resistor; aplurality of supporting non-combustible surfaces separated y intersticesand in closeproximity to said refractory lining; a substantially smoothcombustible sheet material resting against said supporting surfaces;means to introduce nitrogen into said oven; and means to convey theintroduced nitrogen to said tube, substantially as described.

3. In acyanarnid oven, having a tapered inside refractory lining;non-combustible supporting surfaces separated by interstices associatedwith said lining; and a paper lining resting on said surfaces,substantially as described.

4. The process of producing commercial cyanamid, which consists inproviding a cyanamid oven with an upwardly flaring refractory lining;associating with said lining non-combustible supporting surfacesseparated by nitrogen conveying'spaces; resting on said surfacesacombustible lining; providin spaces for an igniting resistor and for te admission of nitrogen to said resistor; substantially filling theinterior of said last named lining with calcium cal-bid except for saidlast named spaces; implanting a lifting means in the carbid charge tofacilitate the removal of the ingot from the tapering oven; admittingnitrogen to said carbid; and igniting the charge, substantially asdescribed.

In testimony whereof I affix my signature, in presence of two witnesses.

GEORGE E. 00X

Witnesses 2 MARGARET Fmi'rr, Louisa WILLS.

